Magento: Dynamic content using Query String in url

app/design/frontend/ultimo/default/template/custompage/careers.phtml

<h1><span>Careers</span></h1>
<h3><span>Click below for more detail</span></h3>
<div class="careers-gallery">
  <div class="careers-gallery-container">
      <ul class="careers-gallery-slideshow">
        <?php 
              $collection = Mage::getModel('careers/careers')->getCollection();
              $counter=1; 
              foreach ($collection as $item) {
                if($item->getfilename()!="" && $item->getstatus()==1){
        ?>          <li class="item grid12-3 <?php if($counter%4==0): echo "last";  endif;?>">
                    <div class="item-img">
                        <a  class="gallery" data-fancybox-group="gallery" title="<?php echo $item->getTitle(); ?>" href="<?php echo Mage::getBaseUrl(Mage_Core_Model_Store::URL_TYPE_MEDIA) .$item->getfilename()?>">
                            <img src="<?php echo Mage::getBaseUrl(Mage_Core_Model_Store::URL_TYPE_MEDIA) .$item->getfilename()?> " alt="" title=""/>
                        </a>
                    </div>
                    <div class="item-content">
                      <?php
                      $link='careers-details.htm';
                      $id= "?id=".$item->getId();
                      $appliid= $item->getId();
                      ?>
                        <a class="gallery" title="<?php echo $item->getTitle(); ?>" href='<?php if($appliid == 11){ echo Mage::getBaseUrl().'applicationform.htm'; } else { echo Mage::getBaseUrl()."$link"."$id"; } ?>'><?php echo $item->getTitle(); ?> </a>
                    </div>
                    </li>
        <?php
                }
                $counter++;
            }
        ?>
      </ul>
  </div>
</div>
<script type="text/javascript">
    jQuery('.gallery').fancybox({
			openEffect : 'elastic',
      openSpeed  : 180,
      closeEffect : 'elastic',
      closeSpeed  : 150,
			loop : false,
			nextEffect  : 'fade',
    prevEffect  : 'fade',
		});
</script>

app/design/frontend/ultimo/default/template/custompage/careers_details.phtml

<?php
$id= $_GET&#91;'id'&#93;;
$collection = Mage::getModel('careers/careers')->getCollection();
foreach ($collection as $item) {
$itemid=$item->getId();
if($itemid==$id){ ?>
<h1 class="page-title"><span><?php echo $item->getTitle(); ?></span></h1>
<div class="hedging-inner">
<div class="hedging-content">
<div class="left-sec">
<div class="detail-img-container">
<div class="img-app-container">
<div class="item-img">
<a  class="gallery" title="<?php echo $item->getTitle(); ?>" href="<?php echo Mage::getBaseUrl(Mage_Core_Model_Store::URL_TYPE_MEDIA) .$item->getfilename()?>">
<img width="200" height="150" src="<?php echo Mage::getBaseUrl(Mage_Core_Model_Store::URL_TYPE_MEDIA) .$item->getfilename()?> " alt="" title="<?php echo $item->getTitle(); ?>"/>
</a>
</div>
<div class="application-form">
<a href="<?php echo Mage::getBaseUrl().'applicationform.htm';?>">
<img title="Click for application form" alt="Click for application form" src="<?php echo $this->getSkinUrl();?>images/dfapplicationformbutton121.png" id="image3">
</a>
</div>
</div>
</div>
<div class="careere-content"><?php echo $item->getContent(); ?></div>
</div>
</div>
<?php /*<div class="grid12-3">
<div class="right-one contact-wraper"><?php echo $this->getLayout()->createBlock('core/template')->setTemplate('custompage/careers_contact.phtml')->toHtml(); ?></div>
</div> */?>
</div>

<?php
}

}
?>
<script type="text/javascript">
jQuery('.gallery').fancybox({
openEffect : 'elastic',
openSpeed  : 180,
closeEffect : 'elastic',
closeSpeed  : 150,
loop : false,
nextEffect  : 'fade',
prevEffect  : 'fade',
});
</script>